Bulkhead assembly for convertible refrigerator cars



Oct. 26, 193 7.

G. c. GEORGE ET AL 2,097,395

BULKHEAD ASSEMBLY FOR CONVERTIBLE REFRIGERATOR CARS Filed Nov. 2, 1936 5 Sheets-Sheet l 61 Z. 20" 24 +3 [26 g g I El 5 25 23 3? 34 22 30 25 29 2 do: 2: -a1 4 2? INVEN TORS 61C. 650/? p5 Ffi Elf/(KL. WOL FF A TTORNEY 1 Oct. 26, 1937. c GEORGE ET AL 2,097,395

BULKHEAD ASSEMBLY EOR CONVERTIBLE REFRIGERATOR CARS Filed Nov. 2, i936 s Sheets-Sheet 2 IN VEN TORS G. C. GEORGE FEEDER/(KL. WOLFF -26, 1937. e. c. GEORGE ET AL 2,097,395

BULKHEAD ASSEMBLY FOR CONVERTIBLE REFRIGERATOR CARS Filed Nov. 2, 1936 3 Sheets-Sheet 3 INVENTORS G. c. GEORGE F/iEoEfi/C/f L. W01. FF

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Patented Oct. 26, 1937 UNITED SA'E'ES tems ATENT FFifi Glenn 0. George and Frederick L. Wolfi, Omaha, Nebr.

Application November 2, 1936, Serial No. 108,866

13 Claims.

The present invention relates to refrigerator cars which are designed to be cooled effectively either by the ordinary water ice or by an evaporative refrigerating system, such as dry ice, and

which may be easily converted from one type of refrigerant to the other.

In pending application, Serial No. 88,042 Glenn C. George has described a car having a central cargo space and ice bunkers at each end, the ice bunkers being in communication with the cargo space at top and bottom for the purpose of permitting the circulation of air when the car is ice-cooled, and having swinging doors for the purpose of closing off such communication when it is desirable to cool the cargo space by a refrigerating system of the evaporative type located within the cargo space, the ice bunkers then serving as insulating spaces to effect a greater efficiency of the evaporative refrigerant.

After a freight car is loaded, it is sometimes desirable to change the method of refrigeration from evaporative to water ice. For example, due to a delay in a long haul at a point where dry ice is not available, and the car having been started on the haul as a dry ice-cooled car, it may be desirable to convert the car to a watericecooled car. It therefore becomes necessary to so construct the ice bunkers and the closures that the latter may be operated from a point outside of the cargo space and preferably outside of the car. It is also important that the closures for the circulating openings operate in such a manner as to be not interfered with by the cargo present in the cargo space.

The solution of the latter problem is the use of closures for the circulating openings that are vertically slidable, and which therefore do not require any space Within the cargo space to operate. However, the use of dry ice as a refrigerant 4o entails a special problem. It is essential to the use of dry ice as a refrigerant at a reasonable cost, that the space containing the goods to be refrigerated, be substantially gas-tight. Ordinarily in freight cars the dry ice is placed in 45 containers at the roof of the car, these containers being open to the cargo space to permit the expansion of the gas. As the dry ice evaporates, the gas, which isv heavier than air, flows downwardly, and being at a low temperature and 50 surrounding the cargo, it cools it and maintains the desired temperature. Any opening or loose joint will permit the escape of this gas, and thus its refrigerating effect will have been lost. Inasmuch as it is the heavy gas at a low tempera- F5 ture that is depended upon to maintain the goods at the desired refrigeration point, it is essential to prevent its escape. It is therefore apparent that the sliding closures above referred to must tightly close the circulating openings so as to prevent appreciable leakage of the gas from the 5 cargo space.

One object of the present invention is to provide a refrigerator car having ice bunkers set off from the cargo space by vertical partitions with circulation openings at their top and bottom, and 10 slidable closures for the openings, with novel means for operating the closures from a point accessible from the outside of the car.

Another object is to provide novel operating means for such slidable bulkheads in which a relatively large force may be exerted to press the bulkheads into their closed position.

Still another object is to provide novel means for tightening the movable bulkheads against the stationary bulkhead when they are in their closed 20 position to prevent the escape of gas into the ice bunkers.

Still another object is to provide a novel operating structure wherein the means for tightening the movable bulkheads against the stationary bulkhead, and the means for operating the movable bulkheads are operated by a single operating device.

Describing the drawings more particularly:

Figure 1 is a longitudinal sectional view of a freight car showing one embodiment of the device.

Figure 2 is a cross sectional view of a freight car showing a form of operating means for the movable bulkheads.

Figure 3 is a sectional view on the line 3-3 of Figure 1, and showing the bulkheads in open position.

Figure 4 is a sectional View on the line 4-4 of Figure 2.

Figure 5 is a vertical sectional View showing the device for tightening the movable bulkheads to its stationary bulkhead.

Figure 6 is a sectional view on the line 6-6 of Figure 4.

Figure '7 is a sectional view on the line 1-1 of Figure 6.

Figure 8 is a sectional view on the line 8-8 of Figure 3.

Figure 9 is a plan View showing a form of connection for the operating means of the movable bulkhead-tightening device and operating device.

Figure 10 is an elevation showing a modified form of operating device.

Figure 11 is an elevation showing another modified form of operating device.

Figure 12 is a sectional view on the line l2|2 of Figure 11.

Figure 13 is an elevation showing a modified form of transmission connecting the bulkhead operating mechanism to the operating device.

Figure 14 is a plan view showing a modified form of connecting the bulkhead-tightening means with the operating means.

Figure 15 is an elevation showing a simplified embodiment of the invention having a different operating means.

Figure 16 is a view on the line ure 15. o

Figure 17 is a view on the line |'||1 of Figure 16.

Figure 18 is an elevation disclosing in addition to the means for opening the bulkheads, a modified mechanism for closing the same.

Figure 19 is a sectional view on the line l9l9 of Figure 18. a v

Figure 20 is a plan view showing a modified operating device.

Describing the drawings more particularly, a freight car 2| has a central cargo space 22 provided with containers for dry ice, or other evaporative freezing apparatus at 23, and provided with means 24 for communicating with these devices. At each end of the cargo space 22 is an ice bunker 25 having a filling hatch 26 at its top,

and set off from the cargo space by a stationary bulkhead 26a.

The bulkheads 26a may advantageously be constructed of spaced frames 21 and 28 disposed about the inner surfaces of the car, and vertical studs 29 supporting between them a partition or stationary bulkhead 30, the studs extending both above and below the stationary bulkhead, and spacing it at its top and bottom from the frame 21, to leave upper and lower openings 3| through which air may circulate between the ice bunker and cargo space. The bulkhead 30 may be constructed in any well-known manner and preferably includes a substantial thickness of insulating material which may be placed between the studding as shown at 21a in Figures 1 and 4 and covered by a wall 28a. The frame 28 is spaced within the ice bunker from the frame 21, and provides at each side of the car a guide channel 32.

Spaced from the stationary bulkheads 26a toward the interior of the ice bunkers 25 are second stationary bulkheads that advantageously may be composed of studs 29a, carrying a central shield member 30a formed preferably of a corrugated metal plate substantially co-extensive with the bulkhead 30, and leaving circulation openings 3la at its top and bottom. The function of this second stationary bulkhead is to protect the sliding closures and their operating mechanism, to be later described, from injury by heavy cakes of ice within the. ice bunkers.

In order to close off the circulation openings 3| when it becomes desirable to convert the car from a water ice-cooled toan evaporative refrigerant cooled car, slidable. closures 33 and 34 are mounted in the channel 32 at the top and bottom of the structure respectively. These closures are movable from a position shown in Figure '2, completely closing the openings 3|, to a position shown in Figure 3, with the openings open to permit air to circulate from the cargo space to the ice bunker and back.

Suitable gaskets 35 are secured to the faces of the movable closures 33 and 34 on the side adjacent the stationary bulkhead 30 to assist in sealing the openings against the passage of carbon dioxide gas. Preferably the top of the upper movable closure 33 and the bottom of the lower movable closure 34 are beveled, as at 36, and the bottom and top members of the frame 28 are beveled to cooperate with the bevels of the closures to give a wedging action towards the stationary bulkhead when the members 33 and 34 are in their closed position.

It is important that the closures be pressed with great force and even pressure to their closed position. To accomplish this, the operating mechanism may include toggle arms.

One embodiment of the operating means may be made as shown in Figures 2and 3. Upon the stationary bulkhead 30 and at each side of the center, are spaced horizontally movable toggle links 31 that may be mounted slidably in straps 38. Pivotally secured at one end to each of the toggle links 37 is a pair of toggle arms 39 that extend respectively above and below the links 31. The distal ends of the arms 39 are pivotally secured to the bottom of the upper closure 33 and the top of the lower closure 34, respectively. It will be readily apparent from consideration of Figures 2 and 3, that when the toggle links 31 are moved inwardly, the arms 39 will be swung outwardly from the links, and will move the closures 33 and 34 to their 'closed position.

Considering Figures 2 and 3, it will be apparent that as the links 31 move inwardly from the position shown in Figure 4, the vertical motion of the closures 33 and 34 will be relatively rapid at first, because the vertical motion of the ends 39 will be large in proportion to the inward horizontal travel of the links 31. However, as the arms 39 approach the end of their swinging motion, the vertical travel will decrease in proportion to the inward travel of the links 31, thus increasing the force with which the closures are moved while decreasing the speed. This increased force is of great value in exerting at the end of the travel a high pressure between the edges of the movable closures and the surfaces against which they seat, assuring a tight joint.

A variety of mechanisms for operating the toggle links may be employed. It has previously been stated that it is desirable to have the sliding closures operable from a position outside of the cargo space, so that entry into the car, or opening the cargo space will be unnecessary. The filling hatches 26 for the ice bunkers make a convenient point from which to operate the mechanism. Operating means may be supported upon the roof of the car in close proximity to the filling hatches 26 and within reach of them, enabling their operation from this point.

One form of operating device is illustrated in Figures 2 to 4 inclusive. In this embodiment, the toggle links 37 are connected by a cable 40 that extends from the ends of the links about pulleys 4! that are disposed between them. An operating cable 42 may be connected to the central portion of the cable 40 by means of a ring 43, through which the cable 43 is freely slidable. The cable 42 extends upwardly within the ice bunker about a pulley 44, that may be suspended from the top of the car, and to a point adjacent the filling hatch 26. Advantageously the end of the cable 42 is provided with a chain 45 that cooperates with a chain-engaging bracket 46 within which it may be engaged to hold the cable 42 taut.

Advantageously the movable bulkheads 33 and 34 are connected by cables 41, as shown in Figures 2 and 3, that pass about pulleys and secure the closures in the well-known counterbalanced manner.

To move the closures to closed position, a second cable 48 may be led about a pulley 49, and provided with a chain 50 adjacent the filling hatches 26 in a manner similar to the arrangement of the cable 42.

The operation of this embodiment is as follows: If it is wished to close the openings 36, the chain 45 may be pulled, causing the links 31 to be moved inwardly, and moving the closures 33 and 34 upwardly, and downwardly, respectively, to closed position. The chain 45 may then be engaged in the bracket 46 and the closures will be fixed in their closed positions. When it is desired to open the structure the chain 50 may be pulled, after disengaging the two chains from the bracket 46, and this will have the effect of raising the lower closure 34 which, through the cable 41 and the collapsing of the toggle arms, will draw the upper one downwardly.

In Figure 10, a modification is shown, in which the toggle arms are pivoted directly together, as by a hinge at 52. The link 31 is omitted in this form and the cable 40 is secured directly to .the pivoted structure.

In Figures 11 to 13 inclusive a modified operating mechanism for the toggle arms is disclosed. In this embodiment, the toggle arms 53 are pivoted to a nut 54, which is threaded upon a horizontally disposed screw 55, the top end portions of the screw being oppositely threaded, whereby rotation thereof will cause the nuts, upon its two ends, to move horizontally in opposite directions. Mounted upon the screw 55 is a bevel gear 56 that is in mesh with a bevel gear 51 carried by an operating shaft 56 that extends upwardly to a point adjacent the filling hatch 26, where it carries a hand wheel 59. It will be readily appreciated that the hand wheel can be turned through the hatch 26 and that rotation in one direction will cause the closures to assume a closed position, while reverse rotation will cause them to open.

In Figure 13 the threaded shaft 55 is disclosed as being provided with a sprocket wheel 66, upon which a sprocket chain 6| runs to a sprocket wheel 62 mounted upon a shaft 63, which carries a crank arm 64 disposed adjacent the filling hatch 26 so as to be operable therefrom.

In Figure 18 is disclosed a modified form of operating means for opening the circulating openings 3|. This is disclosed as being used with the modified form of toggle structure shown in Figure 10, but may be applied to that of Figures 2 and 3. In this form, a cable 65 is secured to the outer side of the toggle structure, as at 66, and is led about pulleys 61 outwardly of the toggle and across the car. A cable 68 is connected with the cable 65 at a point between the toggle structures, as by means of a. pulley 69, from which it is led to an operating device adjacent the filling hatch 26.

As has been explained, it is necessary that the closures, when in closed position, fit tightly against the stationary bulkhead 33 and the frame 21, in order to prevent leakage of gas. Means by which the closures may be tightened against the frame 21 and against the stationary bulkhead 33 are disclosed in Figure 5. As shown in Figures 2,

3, 11 and 12, this structure may be combined with any of the various types of operating means.

The tightening means may be constructed as follows: The movable closures 33 and 34 may be provided upon their sides that are outward with respect to the bulkheads 26a, with rollers 16 that extend into the spaces between the closures and the protective bulkheads. The stationary bulkhead 32 is provided with a pulley or roller 1| located between the closures and inwardly of the rollers 16. A cable 12 is secured to the bottom structure of the assembly, inwardly of the rollers 16, as at 13, from where it is led about the rear of the roller upon the lower closure 34 to the inner side of the pulley it, then about-the roller of the upper closure 33, and then about a pulley 14 supported above the upper opening 3| and inwardly of the rollers 10. The cable 12 is led from the pulley 14 to a convenient point adjacent the filling hatch 26, where it is attached to a suitable operating and securing device. It will be readily apparent that the tension upon the cable 12 controls the pressure of the closures 33 and 34, against the stationary structure over which they slide. As many of the cables 12 as are necessary to ensure uniform tightness across the car may be used.

Due to the heavy pressure required to prevent the escape of gas when the closures are in their tightened position, the frictional contact between them and the stationary structure is so great that the operation of the device would be diificult, and would tend to cause damage to the gaskets. It is therefore desirable to loosen the tightening cables before attempting to move the closures to open position. The cable 12 and the operating cables may be operated by the same operating device, thus insuring that when the closures are in the closed position, the cable 12 is taut, and the necessary pressure exerted against the closures, and also insuring that before the bulkheads are open, the cable 12 is slackened to permit easy operation and prevent damage.

In one system, the cables for moving, and for tightening, the closures may be connected, as shown in Figures 9 and 14. The cables 12 that act to tighten the bulkheads, may be led about a pulley interposed in the chain 45, by means of which the cable 42 is pulled to operate the toggle structure, shown in Figures 2, 3, 4 and 10. The cable lengths are so adjusted that a pull upon the chain 45 will operate first to close the closures to the cable 42, and then to tighten the cable 12. A spring device is inserted to permit operation of the tightening cable after the closures 33 and 34 have reached their closed positions. When the openings 3| are closed and are to be opened, upon disconnecting the chain 45 from the bracket 46, the cable 12 will be loosened, after which a pull upon the chain 50 and cable 48 will move the closures to open position.

In Figure 14 a modification is shown, in which the cables 12 are secured to the ends of a yoke 16 interposed in the chain 45.

Where operating devices of the types disclosed in Figures 11, 12 and 13 are used, the cables 12 may be led to a point adjacent the filling hatch 26, and provided with a link 11 for engaging a locking bracket 18, as shown in Figure 12.

In the cable-operated form of mechanism, a lever may be substituted for the chain and bracket structures disclosed in Figures 4, 9 and 14.

Referring to Figures 15, 16 and 17, it will be seen that the closing cable 42 and the opening cable 48 may be led and secured to the arms of a lever 19 upon the opposite side of its fulcrum 80. The lever, as shown in Figures 16 and 19, is horizontally supported by the roof of the car at a point accessible from the filling hatch 26, and is provided with the usual locking tooth and segment, as shown in Figure 1'7, at 8!. It will be apparent that swinging the lever in a clockwise direction in Figure 17, will close the openings 33, while the opposite movement will open them. In case it is desirable to secure the device in such a manner that the closures may be operated within the cargo space, as sometimes becomes convenient, for purposes of making repairs or cleaning, the latter may be provided with a link 82 that may be swung over to engage the movable portion of the hand grip 83 for operating the locking structure 8!.

Where this form of device is employed, the tightening cables '12 may be associated with an operating cable 84 running about a pulley $5, and then to the side of the lever to which is secured the cable 42, and between the point where the cable 42 is secured and the fulcrum 3G. The point to which the cable 84 is secured having less motion than the point to which the cable 42 is secured, it will be appreciated that the relative lengths of cables 84 and 42 may be easily adjusted so that the cable 84 will be tightened near the end of the motion of the sliding closures. Here too a spring device is inserted to allow for tightening after the closures have reached their closed positions.

In Figure 20 another form of operating means is shown. In this form cables i2 and 85' pass about a pulley 85, secured to the roof of the car, adjacent the filling hatch 26. Operating chains 86 are secured to the cable in advance of the pulley, and brackets 81 for receiving and locking the chains are supported in a convenient position. A pull upon either of the chains serves to open or close the closures, and they may be locked in either position by engaging one of the chains with its bracket.

It is necessary to provide yielding means in the cable-operated forms for holding the closures in their closed positions under a constant pressure in order totake up any slack that may result from the cable stretching and to allow for move ment of the tightening cables after the closures have reached their closed positions. A spring 88, as shown in Figure 9 may be interposed between a head 89 upon a plunger 90 secured to the end of the cable 42 and to the end of a casing 9i, to which the chain 45 is attached. This spring being of the necessary strength, will give the desired result, both in exerting a constant tension upon the closure operating cables, and permitting the tightening operation after the openings 3| are closed.

From the foregoing, it is thought that the construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art without further description and it will be understood that various changes in the size, shape, proportion and minor details of construction may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

What we claim, is:

1. In a refrigerator car having a cargo space and an ice bunker set off from the cargo space by a bulkhead having vertically spaced openings to permit air to circulate between the cargo space and ice bunker, and a movable closure for each ,opening, said closures being spaced vertically,

means for simultaneously operating the closures comprising a horizontally movable toggle link mounted on the bulkhead between the closures, toggle arms having respectivelyone end pivoted to the link and the other to the respective closures, and means for moving the toggle link horizontally.

2. In a refrigerator car having a cargo space, an ice bunker set off from the cargo space by a bulkhead having openings therethrough to permit circulation of air between the cargo space and ice bunker, and a filling hatch in a wall of the car in communication with the ice bunker, a movable closure for each opening in the bulkhead, and means for operating said closures, the closures being located within the ice bunker and adjacent the filling hatch for operation by a person outside of the car.

3. In a refrigerator car, including a cargo space provided with an evaporative refrigerating device, an ice bunker set off from the cargo space by a bulkhead having vertically spaced openings connecting the ice bunker and cargo space to permit air to circulate therebetween, and a hatch in the wall of the car communicating with the ice bunker, a movable closure for each opening in the bulkhead, said closures being slidably mounted adjacent the bulkhead, a pair of toggle rms positioned between the closures in pivoted relation to each other, and each having an end pivoted to one of the closures, and means operable from the filling hatch for swinging the toggle arms to raise or lower the slidably mounted closures. V

4. In a refrigerator car including a cargo space provided with an evaporative refrigerating device, anice bunker set off from the cargo space by a bulkhead having vertically spaced openings connecting the ice bunker and cargo space to permit air to circulate therebetween, and a hatch in the wall of the car communicating with the ice bunker, a movable closure for each opening, said closure being slidably mounted adjacent the bulkhead, a horizontally movable toggle link slidably mounted upon the bulkhead between the closures, a pair of toggle arms, each pivoted at one end to the toggle link, and at the other end to one of the closures, and means operable from the filling hatch for moving the toggle link horizontally.

5. In a refrigerator car including a cargo space provided with an evaporative refrigerating device, an ice bunker set olf from thecargo space by a bulkhead having vertically spaced openings connecting the ice bunker and cargo space to permit air to circulate therebetween, and a hatch in the wall of the car communicating with the ice bunker, a movable closure for each opening, the said closures being slidably mounted adjacent the .bulkhead, horizontally spaced pairs of toggle arms positioned between the closures, each pair comprising an upwardly and a downwardly extending arm pivoted at their upper and lower ends respectively to the movable closures, and pivotally related at their central ends, and means operable from the filling hatch for moving the pivotally related arms to cause the arms to swing and move the closures.

6. In a refrigerator car including a cargo space provided with an evaporative refrigerating device, an ice bunker set off from the cargo space by a bulkhead having vertically spaced openings connecting the ice bunker and cargo space to permit air to circulate therebetween, and a hatch in the wall of the car communicating with the ice bunker, a movable closure for each opening, said closures being slidably mounted adjacent the bulkhead, a, pair of horizontally movable toggle links slidably mounted on the bulkhead between the movable closures, a pair of toggle arms pivoted to each toggle link, the arms of each pair being pivoted respectively to the closures, and means operable from the filling hatch for moving the links toward and away from each other.

7. In a refrigerator car including a cargo space provided with an evaporative refrigerating device, an ice bunker set off from the cargo space by a bulkhead having vertically spaced openings connecting the ice bunker and cargo space to permit air to circulate therebetween, and a hatch in the wall of the car communicating with the ice bunker, a movable closure for each opening, the said closures being slidably mounted adjacent the bulkhead, a pair of horizontally movable toggle links slidably mounted on the bulkhead between the movable closures, a pair of toggle arms pivoted to each toggle link, the arms of each pair being pivoted respectively to the movable closures, a cable connecting the toggle links, and a second cable secured to the first cable between links and extending to the filling hatch for moving the horizontal links.

8. In a refrigerator car including a cargo space provided with an evaporative refrigerating device, an ice bunker set off from the cargo space by a bulkhead having vertically spaced openings connecting the ice bunker and cargo space to permit air to circulate therebetween, and a hatch in the wall of the car communicating with the ice bunker, a movable closure for each opening, the said closures being slidably mounted adjacent the bulkhead, a horizontal threaded shaft rotatably mounted on the bulkhead between the movable closures, a nut threaded on the shaft, tog gle arms having their ends pivoted to the nut and to the movable closures, respectively, a rotary operating device mounted adjacent the filling hatch, and means operatively connecting the threaded shaft and the operating device.

9. In a refrigerator having a cargo space, an ice bunker set off from the cargo space by a bulkhead having an opening therethrough connecting the cargo space and ice bunker to permit air to circulate therebetween, and a. movable closure for the opening, the said closure being slidably mounted adjacent one surface of the bulkhead, means for releasably tightening the movable closure against the surface of the bulkhead, the said means comprising a pulley secured adjacent the surface of the bulkhead at one side of the opening and passing about the movable closure to a pulley mounted adjacent the surface of the bulkhead at the opposite side of the opening, and means for tightening the cable and securing it in taut condition.

10. In a refrigerator car having a cargo space, I

an ice bunker set off from the cargo space by a bulkhead having vertically spaced circulation openings connecting the cargo space and ice bunker to permit air" to circulate therebetween, and a movable closure associated with each opening for closing such opening, each movable closure being slidably mounted adjacent the surface of the bulkhead, means for tightening the movable closures against the bulkhead, the said means comprising a vertically disposed cable secured below the lower circulation opening and adjacent the surface of the bulkhead, the said cable passing around and engaging the sides of the movable closures away from the bulkheads, and between the movable closures and above the upper opening passing through pulley devices mounted adjacent the surface of the bulkhead, and means for tightening the cable and holding it in taut condition.

11. In a refrigerator car having a cargo space and an ice bunker set off from the cargo space by a bulkhead having an opening therethrough connecting the cargo space and ice bunker to permit air to circulate therebetween, a movable closure for closing the opening, the said closure being slidably mounted adjacent the bulkhead and having a surface slidable over the surface thereof, and an operating device for moving the movable closure, means for releasably tightening the movable closure against the bulkhead when in closed position comprising a cable secured at one side of the opening and adjacent the surface of the bulkhead and passing about the movable closure to a pulley device mounted adjacent the surface of the bulkhead and on the opposite side of the opening, the said cable being connected to the device for moving the movable closure in such manner as to tighten the cable when the movable closure is moved to closed position. 7

12. In a refrigerator car having a cargo space, an ice bunker set off from the cargo space by a bulkhead, openings at the top and bottom of the bulkhead connecting the cargo space and ice bunker to permit air to circulate between them, a movable closure associated with each opening and having an inner surface slidable over the bulkhead, and means for operating the closures, including a cable and a device for pulling the cable, means for tightening the movable closures against the bulkhead when the former are in closed position, said means comprising a vertically disposed cable passing over the closures and engaging the surfaces thereof, the said cable being secured at one end to the bulkhead below the lower circulation opening, the cable passing through pulley devices mounted upon the bulkhead between the opening and above the upper opening, the said cable being connected with the device for pulling the bulkhead moving cable to tighten the latter when the closures are in their closed positions.

13. In a refrigerator car having a cargo space, an ice bunker set off from the cargo space by a bulkhead, an opening connecting the cargo space and ice bunker to permit air to circulate between them, a movable closure slidably mounted adjacent the bulkhead within the ice bunker for closing the opening, and mechanism adjacent the closure for moving it, a second bulkhead located within the ice bunker and enclosing the movable closure and its operating mechanism to protect it from contact with ice in the ice bunker, the second bulkhead having an opening corresponding with that of the first bulkhead.

GLENN C. GEORGE. FREDERICK L. WOLFF. 

